A method has been developed for the detection of recombinant bovine somatotropin (rbST) in milk by ESI(+)-LC-MS/MS. This method allowed a detection limit of 20 pg of tryptic N-terminal peptide rbST in standard solution injected on-column and was successfully applied to extracts obtained from milk samples spiked with 50 ng/mL-1 (2.3 pmol/mL-1) rbST.
This document details a method for the detection of recombinant bovine somatotropin (rbST) in milk using Electrospray Ionization Tandem Mass Spectrometry (ESI(+)-LC-MS/MS). The method focuses on the detection of the tryptic N-terminal peptide of the protein, distinguishing between endogenous and recombinant forms based on amino acid sequence differences.
The application utilizes an Agilent 1200 LC system coupled with an Agilent 6410 LC/MS Triple Quadrupole mass spectrometer. The method employs Selected Reaction Monitoring (SRM) mode to achieve high specificity, monitoring specific transitions for rbST, recombinant equine somatotropin (reST), and bovine somatotropin (bST). The technique demonstrated a detection limit of 20 pg of tryptic N-terminal peptide injected on-column and was successfully applied to milk samples spiked with 50 ng/mL of rbST.
| Detection Limit | 20 pg of tryptic N-terminal peptide injected on-column |
|---|---|
| LC Instrument | Agilent 1200 |
| MS Instrument | Agilent 6410 LC/MS Triple Quadrupole |
| Column | Interchrom ModuloCart OS Uptisphere 3HDO 150 mm x 2mm |
| Flow Rate | 0.3 mL/min |
| Injection Volume | 20 pL |
| Capillary Voltage | 5000 V |
| Gas Temperature | 300 °C |
The method achieved a detection limit of 20 pg of tryptic N-terminal peptide rbST injected on-column.
Yes, the method was successfully applied to extracts obtained from milk samples spiked with 50 ng/mL rbST.